Gear-rotor motor-compressor



y 1966 A. E. BROWN ETAL 3,250,459

GEAR-ROTOR MOTOR-COMPRESSOR Filed June 15, 1964 5 Sheets-Sheet 1 FIG. 5

ARTHUR E. BROWN JU IUS A. NAAB ATTORNEY- May 1966 A. E. BROWN ETAL 3,250,459

GEAR-ROTOR MOTORCOMPRESSQR Filed June 15, 1964 3 Sheets-Sheet 3 INVENTORS ARTHUR E ,BROW/V JUL/U5 A. IVAAB TORNEY United States Patent 3,250,459 GEAR-ROTOR MOTOR-COMPRESSOR Arthur E. Brown, Corning, N.Y., and Julius A. Naab, Easton, Pa., assignors to Ingersoll-Rand Company, New 'York, N.Y., a corporation of New Jersey Filed June 15, 1964, Ser. No. 375,231 8 Claims. (Cl. 230-441) This invention relates to motor-compressor devices of the type having eccentrically mounted, intermeshingly toothed rotors which cooperate to form variable-volume fluid displacement chambers between the meshing rotor teeth.

To construct an eflicient gear-rotor motor-compressor of the type described, it is necessary to drive the outer rotor to maintain the tooth clearance in the direction of reducing fluid leakage, provide balanced end thrust pressure on the rotors to effect substantially true rotation of the rotors, and provide inlet and outlet and portings as distinguished from radially disposed inlet and outlet ports, to reduce the clearance volume to a minimum. To achieve balanced end thrust in the rotors, it has been proposed to provide adjacent pairs of rotors. Such con struction is not completely desirable since it results in a relatively complex and expensive apparatus.

Accordingly, it is an object of this invention to provide a motor-compressor device of the character described having a single pair of pressure-balanced rotors so that a relatively simple and inexpensive device is provided.

Another object of the present invention is to provide a motor-compressor device of the character described wherein the clearance volume is at a minimum by provid ing inlet and outlet ports in the end walls.

A further object of this invention is to provide a motorcompressor device of the character described which is capable of being directly driven by a motor.

A still further object of the present invention is to provide in a motor-compressor device of the character described the separation and collection of the lubricant entrained in the fluid to be compressed.

Accordingly, it is contemplated to provide a novel motor-compressor device of the type commonly called a gear-rotor machine comprising an internal gear rotor fixed against the rotation and an external gear rotor eccentrically disposed and in meshing relationship with the internal gear rotor. The external gear rotor is journaled on a crankshaft which is driven by a motor so that the external gear rotor moves relative to the internal gear rotor to form variable-volume fluid displacement chambers between the meshing teeth. The porting discs carried by the crankshaft are disposed on opposite sides of the external and the internal gear rotors. The porting discs are provided with inlet ports communicating at one end with a source of gaseous fluid and with opposite sides of the fluid displacement chambers. The porting discs are also provided with outlet ports which communicate with the opposite sides of the fluid displacement chambers and a fluid discharge passage which conducts the gaseous fluid to a place of use or storage. To effect the separation of the entrained lubricant from the gaseous fluid, the discharged gaseous fluid is conducted into a lubricant sump where the gaseous fluid bubbles up through a reservoir of lubricant and thereby removes the lubricant from the gaseous fluid.

The invention will be more fully understoodtrom the following description when considered in connection with the accompanying drawings in which:

FIG. 1 is a view, in elevation, of a motor-compressor device according to this invention;

FIG. 2 is a longitudinal, sectional view taken along line 22 of FIG. 1, substantially enlarged;

'FIG. 3 is a cross-sectional view taken along line 33 of FIG. 2;

FIG. 4 is a view, in cross section, taken along line 4-4 of FIG. 2; and

FIG. 5 is a fragmentary cross-sectional view taken substantially along line 55 of FIG. 4.

Now referring to the drawings, 10 generally designates a motor-compressor device, commonly called a gear-rotor machine, which is shown mounted on a storage tank 11. The motor-compressor device 10 will be described as applied to the compressing air, but it is to be expressly understood that the device may be employed to compress any gaseous fluid or may be employed as a motor without departing from the scope and spirit of this invention.

Motor-compressor device 10 comprises a housing 12 in the upper portion of which is mounted a motor 13, such as an electric motor. A gear-rotor assembly 14 is disposed in the intermediate portion of the housing, while the lower portion of the housing forms a lubricant-fluid reservoir or sump 15. A crankshaft 18 is journaled in bearings 19 and 20 mounted in transverse partition walls 21 and 22, respectively, of housing 12. The armature or rotor (not shown) of motor 13 may be an integral part of crankshaft 18 or may be connected to the crankshaft to rotatively drive the latter. Between partition walls 21 and 22 is defined a chamber 23 in which is disposed gearrotor assembly 14.

Gear-rotor assembly 14 comprises an outer, internally toothed gear rotor 24 and an inner, externally toothed gear rotor 25 disposed between a porting plate 26 formed integral with crankshaft 18 and a second porting plate 27. Gear rotor 25 is mounted on a crank pin portion 28 of crankshaft 18 in eccentric relationship with the axis of the crankshaft and the axis of gear rotor 24 (see FIG. 3). Gear rotor 25 is mounted on a full-floating sleeve bearing 29. Gear rotor 24 is held against rotation, although it is free to float axially, by a pin 30 which projects through a hole 31 in a longitudinally extending wall of housing 12 into a slot 33 in the surface of gear rotor 24.

To provide for the introduction of gaseous fluid, such as air, to be compressed into the gear-rotor assembly 14, housing 12 has a primary air intake port 34 which communicates the atmosphere with an intake chamber 35 formed on housing 12 by cap 32. A pair of secondary intake ports 36 is provided in the Wall of housing 12 adjacent outer gear rotor 24 to pass the air over the rotor into chamber 23 and thereby remove heat and help cool the assembly. Another secondary intake port 36A provides for the flow of the air from intake chamber 35 into chamber 23. To provide for the conductance of the air into the variable-volume compression chambers 37 formed by the meshing teeth 38 and 39 of gear rotors 24 and 25, respectively, a pair of inlet ports 40 and 41 is formed in porting plates 26 and 27, respectively. The compressed air is conducted from compression chambers 37 by a pair of outlet ports 42 and 43 which are provided in porting plates 26 and 27, respectively. Since the air to be compressed is introduced into compression charm bers 37 from opposite sides of gear rotors 24 and 25 by inlet ports 40 and 41 and the compressed air is discharged from opposite sides of the gear rotors through outletports 42 and 43, gear rotors 24 and 25 are pressure-balanced so that the rotors will not tilt or cant with respect to its true rotative position and line contact'between gear-rotor teeth '38 and 39 is assured. To provide for the flow of the fluid into inlet port 41, an annular groove 24A is formed in the outer surface of gear rotor 24 and a plurality of longitudinal slots 24B are provided to communicate groove 24A with chamber 23. Groove 24A is in direction com munication with intake ports 36. Outlet ports 42 and 43 communicate with an axial bore 44 in crankshaft 18,

operating principle in detail.

3 extending from the distal end of the crankshaft to integral porting plate 26.

The operating principle of a motor-compressor device of the gear-rotor type herein-described is well known in the art; and it is, therefore, unnecessary to set forth the i For detailed information regarding the operating principle of this type of motorcompressor, reference is made to US. Patent No. 2,547,392 issued April 3, 1951, to M. P. Hill et al.' It is believed sufficient merely to recite that gaseous fluid, such as air, is drawn through inlet ports 40 and 41 into compression chambers 37 by the suction created as inne'r gear rotor. 25 planetates under the urging of crank pin portion 28 and rotates relative to outer gear rotor 24. The air compressed in chambers 37 is discharged through outlet ports 42 and 43, into bore 44, and thence into sump 15.

As shown in FIG. 5, a means for lubricating and cooling gear-rotor assembly 14 is provided in motor-compressor device 10. This means includes a tube 45 which is connected at one end, through an elbow 46, to an end plate 47 and extends into a reservoir of lubricant in sump 15. End plate 47 surrounds a flanged thrust collar 48 and abuts partition wall 22. Thrust collar 48 is slidably receivable on crankshaft 18 and in abutment against hearing 20. A nut 49 is turned upon the threads 50 formed on crankshaft 18 to abut collar 48 and thereby secure gear-rotor assembly 14 in assembled relationship within housing 12. A passage 51 is provided in end plate 47 to communicate elbow 46 with a hole 52 in thrust collar 48. A longitudinal groove 53 is provided in crankshaft 18 to conduct the lubricant from hole 52 to a lubricant passageway 54 in porting plate 27. A restricted passage 55 communicates passageway 54 with the interstices or compression chambers 37 between teeth 38 and 39 of gear rotors 24 and 25 to provide for the injection of the lubricant directly between the teeth. The lubricant injected into chambers 37 is entrained in the air being compressed and is carried by the compressed air into the reservoir of lubricant through bore 44 in crankshaft 18. As the air bubbles up through the reservoir of lubricant, the particles of the entrained lubricant are removed from the air;

To prevent the leakage of discharged air back into chamber 23 from sump 15, a ring 56 having a sealing face 57 is disposed over thrust collar 48 between end plate 47 and the flange of thrust collar 48.. A wavy spring 58 is disposed between the flange and ring 56 to bias sealing face 57 of ring 56 against end plate 47. The interstices between thrust collar 48 and ring 56 are sealed by an O- ring 59.

The compressed air is conducted from sump 15, through an air outlet connection 60 secured to housing 12, to the interior of tank 11 or to some other point of use or storage. A check valve 61, schematically shown in FIG. 2 since any check valve of well-known construction may be employed, is disposed in the outlet connection to prevent the backflow of the compressed air from the outlet connection into sump 15 when the unit is shut down.

It is believed now readily apparent from the foregoing description that a novel gear-rotor motor-compressor device has been provided which is of compact construction and of high efliciency since the gear rotors are pressure-balanced and the torque tends to close the clearance between the gear rotor teeth. It is a device wherein the gear-rotor assembly is directly rotatively driven by a motor. It is also a device wherein a means for lubricating and cooling the unit is provided, which means includes a simple means for removing the entrained lubricant from the compressed gaseous fluid.

Although but one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the arrangement of parts Without departing from the spirit and scope of the 4 invention as the same will now be understood by those skilled in the art.

We claim:

1. A fluid motor-compresser device comprising (a) a shaft having an eccentric portion,

(b) a motor connected to rotatively drive said shaft, (0) a first rotor having external teeth journaled on said eccentric portion, (d) a second rotor having internal teeth disposed eccentrically with respect to said first rotor and in meshing relation with the teeth of said first rotor,

(e) a wall means disposed on opposite sides of said rotors and fixed on the shaft to rotate with the latter,

(f) fluid inlet ports in said wall means to conduct the fluid to be compressed into the spaces between the meshing teeth of said first and said second rotors,

(g) fluid outlet ports in said wall means to receive the compressed fluid from the spaces between the meshing teeth of the first and the second rotors, and

(h) a bore in said shaft communicating with said outlet ports to conduct the compressed fluid to a place of use or storage.

2. A fluid motor compressor device comprising (a) a shaft having an eccentric portion,

(1)) a motor connected to one end of said shaft to rotatively drive the shaft,

(c) a means defining a lubricant reservoir,

(d) the distal end of said shaft projecting into said lubricant reservoir, (e) a first rotor 'having external teeth journaled on said eccentric portion of the shaft,

(f) a second rotor having internal teeth disposed eccentrically with respect to said first rotor and in meshing relation with the teeth of said first rotor,

(g) said second rotor being fixed against rotative movement so that the first rotor planetates and rotates relative to the second rotor to form variable-volume displacement chambers between the teeth of said first and said second rotors,

' (h) a wall means carried by said shaft and disposed on opposite sides of said first and said second rotors, (i) fluid inlet ports in said wall means to conduct the gaseous fluid to be compressed into the variablevolume displacement chambers,

(j) fluid outlet ports in said Wall means to conduct the compressed gaseous fluid from the variable-volume displacement chambers,

(k) a bore in said shaft extending from the distal end thereof and into communication with the outlet ports to receive and conduct the compressed gaseous fluid into the lubricant in said lubricant reservoir, and

'(l) a conduit means for conducting the compressed gaseous fluid from the reservoir to a place of use or 4 storage.

3. The apparatus of claim 2 wherein said inlet and said outlet ports extend substantially parallel to the axes of said rotors and communicate with the opposite sides of 'the variable-volume displacement chambers.

4. A fluid motor-compressor device comprising (a) a shaft having an eccentric portion intermediate the ends thereof,

(b) a motor directly connected to rotatively drive the shaft,

(-0) a means defining lubricant,

(d) the distal end of said shaft projecting into said eccentric portion of the shaft,

(e) a; first rotor having external teeth j ournaled on said eccentric portion of the shaft,

(f) a second rotor having internal teeth disposed eccentrically with respect to said first rotor and in meshing relation with the teeth of said first rotor,

(g) said second rotor being fixed against the rotation so that the first rotor pl anetates and rotates relative to the second rotor to form variable-volume displacea reservoir for holding liquid ment chambers between the .teeth of said first and said second rotors,

(h) a first end porting plate integral with said shaft abutting one side of said first and said second rotors,

(i) a second end iporting plate carried by said shaft and disposed in abutment on the opposite side of said first and said second rotors,

(j) a fluid inlet port in said first and said second porting plates communicating with the variable-volume displacement chambers to conduct the gaseous fluid to be compressed into the latter,

(k) a fluid outlet port in said first and said second porting plates communicating with the variable-volume displacement chambers to conduct the compressed gaseous fluid from the displacement chambers,

(l) a bore in said shaft extending from the distal end thereof and in communication With the outlet port to receive and conduct the compressed gaseous fluid into the lubricant in said reservoir, and

(m) a conduit means for conducting the compressed gaseous fluid from the reservoir to a place of use or storage.

5. The apparatus of claim 4 wherein passage means is provided in communication with the reservoir to receive the lubricant and With the variable-volume displacement chambers to :conduct the lubricant to the latter.

6. A fluid motor-compressor device comprising (a) a housing,

(b) a motor in said housing,

(0) a shaft journaled for rotation in said housing and connected at one end to said motor to be rotated by the latter,

(d) said housing defining therein a reservoir in one end thereof for holding a quantity of the liquid lubricant,

(e) the distal end of said shaft extending into said reservoir and into the liquid lubricant,

(f) said shaft having an enlarged eccentric portion intermediate the ends of the shaft,

(g) a first end porting plate integral with the shaft disposed adjacent said eccentric portion,

(11) a second end porting plate carried by said shaft and disposed adjacent the eccentric portion opposite from the first end porting plate,

(i) a first rotor having external teeth journaled on said eccentric portion of the shaft and between the first and the second porting plates,

(j) a second rotor having internal teeth secured in said housing against the rotation and disposed eccentrically with respect to and in meshing relation with the first rotor so that the first rotor planetates and rotates relative to the second rotor to form variablevolu-me fluid displacement chambers between the teeth of said first and said second rotors,

(k) a fluid inlet port in said first and said second porting plates communicating with the variable-volume displacement chambers to conduct the gaseous fluid to be compressed into the latter,

(1) a fluid outlet port in said first and said second porting plates communicating with the variable-volume displacement chambers to receive the compressed gaseous fluid from the latter,

(m) a passage in said shaft extending from the distal end thereof and in communication with the outlet port to receive and conduct the compressed gaseousfluid into the lubricant in said reservoir, and

(-n) a conduit means connected to said housing for conducting the compressed gascous fluid from the reservoir to a place of use or storage.

7. The apparatus of claim 6 wherein said inlet and said outlet ports extend substantially parallel with the axis of said shaft.

8. The apparatus of claim 6 wherein the passage means communicates with the lubricant in said reservoir and with the variable-volume displacement chambers to conduct the lubricant to the latter.

References Cited by the Examiner UNITED STATES PATENTS 2,011,338 8/1935 Hill 23G141 2,547,392 4/1951 Hill et al 103126 3,133,694 5/1964 Luck 230141 3,157,350 11/1964 Fraser 230141 X ROBERT M. WALKER, Primary Examiner. 

1. A FLUID MOTOR-COMPRESSER DEVICE COMPRISING (A) A SHAFT HAVING AN ECCENTRIC PORTION, (B) A MOTOR CONNECTED TO ROTATIVELY DRIVE SAID SHAFT, (C) A FIRST ROTOR HAVING EXTERNAL TEETH JOURNALED ON SAID ECCENTRIC PORTION, (D) A SECOND ROTOR HAVING INTERNAL TEETH DISPOSED ECCENTRICALLY WITH RESPECT TO SAID FIRST ROTOR AND IN MESHING RELATION WITH THE TEETH OF SAID FIRST ROTOR, (E) A WALL MEANS DISPOSED ON OPPOSITE SIDES OF SAID ROTORS AND FIXED ON THE SHAFT TO ROTATE WITH THE LATTER, (F) FLUID INLET PORTS IN SAID WALL MEANS TO CONDUCT THE FLUID TO BE COMPRESSED INTO THE SPACED BETWEEN THE MESHING TEETH OF SAID FIRST AND SAID SECOND ROTORS, (G) FLUID OUTLEEWT PORTS IN SAID WALL MEANS TO RECEIVE THE COMPRESSED FLUID FROM THE SPACED BETWEEN THE MESHING TEETH OF THE FIRST AND SECOND ROTORS, AND 